How to add holidays to everyone's outlook calendars

I need to be able to push American and Canadian holidays to users outlook calendars. We are on Exchange 2010 and have users with Outlook 2003,2010, and 2013.

Is there a way to push it from the server? So far my best idea is to create an invite which I would hope all my users accept for each holiday.

Any ideas welcome, and i am willing to use power-shell if needed.

Thanks in advance,

Tim